Hardness test machine



' 23, 1940. c. E. SMITH HARDNESS TEST MACHINE Filed 001:. 2, 1937 3nvntor attorneys Patented Apr. 23, 1940 UNITED STATES PATENT OFFICE HARDNESS TEST MACHINE Application October 2,

7 Claims.

This invention relates to means for testing and indicating the hardness of metal, and more particularly to a machine for the purpose wherein the hardness of the metal tested, is determined by the depth of penetration of a member into the metal.

In machines or devices of this character where the full length of the penetrating stroke is effective in operating an indicator, the resulting indication is modified by including the initial part of the penetrating stroke or that part which penetrates the skin or surface layer of the metal, and an incorrect indication as to the hardness of the interior or body of the metal is therefore shown by the indicator.

It is therefore essential that this initial part of the penetrating stroke of the penetrating member be ineffective to operate the indicator and it is an object of the present invention to provide, in a machine of this character, simple and effective mechanical means whereby the initial part of the stroke of the penetrating instrumentality is eliminated as a factor of the indication by the indicator.

' It is also an object to provide means whereby the length of this initial portion of the penetrating stroke may be increased or diminished according to the character of the metal being tested, such means being quickly and easily adjusted.

A further object is to provide a machine of this character with yieldable means to which force is applied for effecting penetration and which yieldable means will operate in yielding, to effect an operative connection between the means for moving the penetrating means and means for effecting operation of an indicator, so that said yieldable means may yield a limited amount before such connection is made to operate the indicator, the force applied to cause such yield being suflicient to cause penetration of the skin of the metal. Said connecting means has a gripping action to efiect such connection after a predetermined yielding movement of said yielding means, and the construction is such that the initial part of the penetrating stroke prior to the operation of the indicator may be increased or decreased in length, such adjustment to be made in accordance with the character of the metal being tested.

A further object is to provide a machine for the purpose which is simple in construction and efiective in correctly indicating the hardness of the metal being tested, and to provide certain other new and useful features in the construc- 1937, Serial No. 166,907

tion, arrangement and combination of parts, all as hereinafter more fully set forth, reference being had to the accompanying drawing in which Figure 1 is a side elevation of a machine illustrative of an embodiment of the present inven- 5 tion with a portion broken away and in section to disclose the construction;

Fig. 2 is an end elevation of the machine taken at right angles to that of Fig. 1 and partlyin section, substantially upon the line 22 of Fig. 1; 0

Fig. 3 is an elevation of an indicator shown in side elevation in Fig. 1;

Fig. 4 is a transverse section substantially upon the line 4-4 of Fig. '2, and

Fig. 5 is an enlarged sectional detail substan- 15 tially upon the line 5-5 of Fig. 2.

As shown, the machine comprises a vertically extending frame I having a base 2 and an upwardly extending portion which is shown as embodying or including a suitable cylinder 3 indi- 20 cated in dotted lines in Fig. 1 and within which cylinder is an hydraulically operated piston 4, the construction of said hydraulically operated device being of any old and well known construction wherein the piston is operated within its cylinder by fluid under pressure supplied to the cylinder by any suitable means not shown. The piston 4 is provided with a downwardly extending plunger rod 5 guided within the frame in any suitable manner and adapted to be moved endwise by the piston by means of hydraulically applied force which is indicated by a suitable indicator, not shown, so that the operator of the machine may know the amount of force applied to the metal being tested and which metal test piece 6 or other part to be tested, is placed upon a table 1 supported by an adjusting screw 8 carried by the base 2 and adjusted by means of a hand wheel 9 to raise or lower the table toward or from the lower end of an auxiliary plunger H] which carries a hardened ball H adapted to be forced downwardly by the hydraulic pressure into the test piece or work 6. This auxiliary plunger I0 is in vertical longitudinal axial alinem-ent with the hydraulically operated piston rod 5 and is guided in its movement in a bearing l2 on the lower end of a guide bracket [3 secured at its upper end to the head or upper end portion of the frame I which carries the cylinder 3.

Interposed between the lower end of the rod or plunger 5 and the upper end of the auxiliary plunger III, is a block 54 to the lower side of which the auxiliary plunger It is rigidly secured in any suitable manner as by screwthreading its upper end to engage within a screwthreaded bore in the block. Above the block M which is elongated transversely of the machine, is a bar l5 resting upon a pair of pins 15 extending transversely of the block M adjacent the ends of the block and resting within notches or depressions formed in the upper side of the block Hi and in the lower side of the bar I5. The hydraulically operated plunger rod 5 is adapted to engage at its lower end, the upper side of the bar If; intermediate the two supports Pi, and the bar l 5 is loosely held in place relative to the block 54 by means of bolts ll extending through openings in said block and bar adjacent their ends. The bar i5 is therefore supported upon the block as in such a manner that it will yield under pressure applied thereto by the plunger rod 5, such pressure being applied when the ball ii is in contact with the work 6 to resist the downward movement of the block 4, and thereforepressure applied to the bar 55 by the plunger will be transmitted to the block M and through the auxiliary plunger Hi to force said plunger downwardly and cause the ball H to penetrate the surface of the work.

Rigidly mounted within an opening in the guide bracket I3, is a channel bar l 3 which channel bar forms a rigid support for an indicator iii of any suitable form or construction and which is mounted rigidly upon the outer end of the channel bar it, said indicator having a movable stem 2!] for operating the hand of the indicator in the usual manner, said stem being adapted to engage the outer end of a rocker bar 2i which is pivotally supported as at 22 intermediate its ends within the channel of the channel bar iii. The opposite or inner end of this rocker bar 2! extends inwardly toward and above the front side of the bar i5 and loosely attached to this inner end of the rocker bar, is a thin flexible metal strip 23 adapted to lie flat against the outer side of a plate 24 secured in any suitable manner to the front side of the block l4 and extending upwardly in contact with the side of the bar 15 above. A yoke member 25 has side arms 26 extending downwardly at each side of the plate 2 1- with the lower ends of these arms pivotally attached to the plate by means of a transverse pivot 21. The side arms or legs 26 of this yoke are connected at their upper ends by a transverse bar 28 which projects laterally from the arms 26 and over the yieldable bar I 5 in spaced relation to the upper'side thereof, and this bar is provided with a screwthreaded opening intermediate its ends to receive an adjusting screw 29 adapted to engage at its lower end the upper surface of the bar l5 intermediate the ends of said bar. Secured to the arms 26 of the yoke member 25 is a gripping strip 3!] which extends transversely of the thin flexible strip 23 adjacent its upper end and adjacent the upper edge of the plate 2d. Normally this gripping bar or strip 30 is held just slightly out of contact with the strip 23, by the adjusting screw 29 resting upon the bar I 5 and preventing swinging movement of the yoke 25 to bring the bar 3b into gripping contact with the strip 23. The yoke 25 is normally held with its adjusting screw 29 in contact with the upper surface of the bar I5 by means of light flexible springs 3! and therefore when the bar I5 is bent or caused to yield downwardly intermediate its ends by the pressure of the piston rod or plunger 5, the yoke 25 will swing toward the edge of the bar l5 due to this yielding movement of the bar in contact with the upper side of which the adjusting screw 29 is held by means of the springs 3|. This swinging movement of the yoke 25 which is permitted by the downward yield of the bar l5, brings the gripping bar 3! into gripping contact with the flexible strip 23, looking this strip 23 in face contact with the plate 24 so that fur ther pressure applied by the plunger 5 and transmitted by the bar E5 to the block i4, and thence to the auxiliary plunger 20, will move the strip 23 with the block I4 and through the connection of the upper end of this strip 23 with the end of the rocker bar 24, will rock the rocker bar upon its pivot 22 and cause its outer end to swing upwardly into engagement with the stem 26 of the indicating device to operate said indicator.

The bar i5 is normally held in contact with the lower end of the plunger 5, and the block M, together with the auxiliary plunger 10, is held in raised position, by means of coiled springs 32 connected at one end to arms 33 projecting laterally from the head of the frame i and at their lower ends to cars 34 secured to the lower side of the block M, and in the normal operation of the machine, the table l supporting the Work 6 or test piece, is adjusted vertically to bring the work into firm contact with the ball ll so that the initial or first part of the pressure movement of the plunger 5 will apply force directly to the auxiliary plunger It to cause the ball to pene trate slightly into the surface of the work. It is not, however, desirable that this initial movement which causes a penetration of the skin or immediate surface of the work test piece, be recorded or indicated upon the indicator I!) as such surface of the test piece may be much hardor or much softer than its body or interior which determines the real hardness of the metal.

Therefore the initial force applied by the plung er 5 and transmitted by. the bar 15 and block M to the auxiliary plunger I!) will be just suflicient to cause the ball to penetrate the surface of the work but this force will be sufficient to bend the bar !5 and by such bending cause the yoke 25 to swing inwardly and bring the bar 30 carried thereby into gripping engagement with the strip 23 so that further downward pressure by the plunger 5 which will move the auxiliary plunger ill and cause further penetration of the ball into the work, will also move the strip 23 downwardly with the downward movement of the block M and this portion of the penetrating stroke will be indicated by the indicator H2. The force required to drive the plunger Hi throughout the portion of the penetrating stroke indicated by the indicator, being known, the exact hardness of the interior of the work may be accurately calculated from such indication.

The length of the initial penetrating movement may be readily adjusted to suit the nature of the metal being tested, by simply adjusting the screw 29, as the further it is adjusted inwardly the greater must be the flexure of the bar I 5 before the yoke 25 is brought into gripping engagement with the strip 23 and the longer will be the initial part of the penetrating stroke to pierce the scale or skin of the metal before the indicator is actuated, and contra, outward adjustment of said screw will shorten this initial part of the stroke. Therefore very simple and accurate adjustment is secured to vary the length of this initial portion of the stroke according to the nature or thickness of the skin of the metal being tested.

Obviously changes may be made in the construction and arrangement of parts without departing from the spirit of the invention, and. such changes are contemplated.

Having thus fully described my invention what I claim is:

l. A machine for the purpose described including a pressure plunger, a longitudinally movable member in axial alinement with said plunger and carrying a penetrating instrumentality at its end to penetrate the metal being tested, an indicator, means interposed between said plunger and longitudinal movable member including a block to which the longitudinally movable member is secured at one end, a bar supported upon said block and adapted to flex intermediate its ends, said bar being flexible by said plunger, a member pivotally attached to said block and extending over said flexible bar and provided with means for engaging said bar to operate said pivoted member upon flexing movement of the bar, and a member to operate said indicator and adapted to be gripped by said pivoted member to effect an operative connection between saidblock and said indicator.

.2. A machine as characterized in claim 1, in which said member which is pivotally attached to said block and said means carried by said pivoted member for engaging said flexible bar, are adjustable relative to said longitudinally movable member to adjust the length of the initial penetrating movement.

3. A machine for the purpose described including a supporting frame, a work supporting table carried by said frame, a pressure applying plunger guided by said frame, an auxiliary plunger mounted for longitudinal movement in longitudinal axial alinement with said pressure applying plunger, said auxiliary plunger having a penetrating member to penetrate work supported by said table, an indicator for indicating the depth of penetration, a block to which the upper end of said auxiliary plunger is secured, a bar supported adjacent its ends upon said block for flexing movement and to the intermediate portion of which bar pressure is applied by said pressure plunger, a pivoted member pivotally attached at its lower end to said block and extending laterally over said bar, means for yieldingly swinging said member toward said block and bar, adjustable means carried by said pivoted member for engaging the upper surface of said bar, a member for operating said indicator, and a flexible strip connected to said indicator operating member and adapted to be clamped by swinging movement of said pivotally supported member toward said block and bar to operatively connect said block and said indicator.

4. A machine for the purpose described and as characterized in claim 3, and wherein said member which is pivotally attached to said block in the 'formof a yoke and is provided with a transverse bar to swing with said pivoted member and clamp said flexible strip between it and said block.

5. A machine for the purpose described including a longitudinally movable member having a penetrating instrumentality at its lower end, means for guiding said member in its longitudinal movement, a block secured to the upper end of said member, a bar supported upon said block in spaced relation thereto and mounted adjacent its ends upon said block for flexing movement toward and from the block intermediate its ends, a pressure applying plunger to engage said bar intermediate its ends and flex said bar by initial pressure applied by said plunger, an indicator for indicating the depth of penetration by the penetrating instrumentality, a pivoted bar for operating said indicator, a yoke pivotally attached tosaid block at one side thereof and having a portion extending laterally over said flexible bar in spaced relation thereto, adjustable means carried by said yoke to engage the upper surface of said flexible bar, a flexible strip member attached to the inner end of said pivoted bar for operating said indicator, and means carried by said yoke for engaging and clamping said flexible strip upon flexing of said bar under pressure and the swinging of said yoke toward said block and bar.

6. A machine for the purpose described including a supporting frame, a work supporting table carried by said frame, a power applying plunger movable in said frame and extending in a vertical direction, an auxiliary plunger in vertical axial alinement with said plunger and having a penetrating instrumentality at its lower end to engage and penetrate the work supported by said work table, a block secured to the upper end of said auxiliary plunger, a bar supported upon said block by spaced apart supports and adapted to flex under pressure applied by said plunger intermediate the supports for said bar, yieldable means for holding said bar in contact with the lower end of said power applying plunger, an indicator for indicating the depth of penetration of the work by said penetrating instrumentality,

a bracket secured to said frame and providing a guide bearing for said auxiliary plunger, a channel bar rigidly secured within an opening in said bracket and upon the outer end of which said indicator is supported, a rocker bar pivoted intermediate its ends within said channel bar with its outer end adapted to engage means for operating said indicator, a member attached to the inner end of said rocker bar and extending downwardly adjacent said block carried by said auxiliary plunger, a yoke member pivotally attached at its lower end to one side of said block to swing toward and from the block and having .a laterally projecting portion extending over the upper side of said flexible bar in spaced relation thereto, an adjusting screw carried by said yoke, yieldable means for holding said yoke swung toward said block and bar with said adjusting screw engaging the upper surface of said flexible bar, and means carried by said yoke for engaging said flexible strip upon. swinging movement of said yoke toward said block and flexible bar to operatively connect said block and the inner end of said rocker bar for operating said indicator, upon initial application of pressure to said flexible bar and the flexing of said bar to swing said yoke.

7. In a hardness testing machine having a movable penetrator and a hardness indicator, a clutch mechanism for operatively connecting the penetrator and the indicator comprising, a support movable with the penetrator, a resilient member operatively connecting the penetrator and a force exerting means, a clutch member connected to the indicator, a second clutch member cooperable with said first-named clutch member and pivoted to said support, spring means acting to pivot said second-named clutch member into clutching relationship with said first-named clutch member, and an adjustment member carried by said second-named clutch member and abutting said resilient member.

CLARENCE? SMITH. 

